Today's amplifiers are called upon to cover a broader dynamic range than previous amplifier generations. For this reason, amplifier circuits are designed to have their supply voltage large enough to handle a maximum input signal without clipping by setting the operating point of an amplification device at an optimum fixed value for such a supply voltage.
However, since the operating point and the supply voltage of such amplifier circuits are primarily set to handle such a large input signal level with minimum distortion, a large amount of operating current, which would not be needed otherwise, will flow even with a small input signal level. In addition, the period during which a maximum input signal is driven into the amplifier circuit is relatively short, thus a large amount of idle current may pass through the amplification device, and this results in unfavorable power consumption, poor amplifier efficiency and durability. Additionally, this situation can create an excessive amount of heat due that can damage the amplification device.
One solution to this problem is to include heat dissipation technologies, such as a heat sink, in the amplifier. Heat sinks may remove the excessive heat resulting from the increased power on the amplification circuitry, which results from the large current and supply voltage. However, heat sinks add weight and cost to the amplifier and are thereby less than desirable solutions for this problem. Plus, even with the implementation of heat sinks in the amplification device, the excessive power dissipated by the amplification circuitry can still result in amplifier damage.
Other solutions include constantly monitoring the amplifier output and then adjusting the supply voltage accordingly so as to keep the power dissipated in the amplifier circuitry within tolerable levels. To accomplish this constant monitoring, additional expensive and complex circuitry is required in the amplifier, which introduces more components that may fail. These additional components oftentimes introduce additional delay, as it is difficult for this type of amplifier to yield a fast transient response.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.